Best Intentions
by SecretKata
Summary: 'I had the best intentions – and now my family is in danger because of me. I need to fix this, even if it costs me my life.' Donatello. Things go awry for the turtles when a rescue mission goes wrong, and they may never be the same again.
1. Chapter 2

Within the lab Donatello sat at his desk with various instruments at hand; a beaker filled with the familiar glowing turquoise solution known as mutagen; a conical flask containing no more than 10 ml of transparent liquid, and a pipette in his grasp of three fingers. He squeezed the pipette adding a drop of mutagen into the conical flask and breathed a heavy sigh as the liquid continued to glow that pretty turquoise hue.

Donatello sank to the back of his chair with disappointment. "I'm never going to get this to work" sighed Donatello, who returned to his computer monitor and typed an entry – "NEG''. He had run so many tests that he was too lazy to even type negative anymore. He wasn't really in the mood for the surprising outburst from the familiar face with an orange mask that suddenly disturbed the silence of the lab.

"Yo Dee, I made pizza'' said Mikey, almost singing the last word. Despite the seemingly unhealthy diet consisting of pizza, all four turtles carried a good figure. Although Mikey was the youngest of the four (and his enthusiasm for training not as strong as others), it did not affect his muscular frame and speed. He was the fastest of the brothers and managed perfectly well during training and in battle. Donatello was the tallest of the brothers, 5ft 10 to be precise, and would normally have a bow staff strapped to his back, but not today. He was aiming to progress in science, not in physique like his brothers who were probably beating up Kraang droids on their scouting mission. Donatello was more slender and looked rather different compared to the most aggressive of the four turtles, Raphael, who was more muscle built and much stronger.

Donatello shrugged off Michelangelo's announcement of food. 'Not now, Mikey. I am busy trying to create this retro-mutagen I've been working on.'

'Dude, you've been at that for weeks now,' complained Mikey. Donatello almost felt like scolding at Mikey for his inaccuracy. It had been months not weeks!

'Urgh, I'm running out of mutagen again. Have Leo and Raph come back yet? I'm hoping they've found some more so that I can continue my work.'

'Sorry Dee, don't think so. They would've come running if they knew I was cooking' he said with that cheeky grin of his. Donatello almost felt jealous at his brother for being so cheerful but brushed that thought aside. It wasn't Mikey's fault. He delved into the thought that it was his _own_ fault that the mutagen canisters fell out of the Kraang ship, distributing themselves all over New York. It was _his_ fault he asked April and her father to help scout out the ship in the first place, leading to Mr O'Neill being a subject of alien science and transforming into the bat/pig…not monster…creature that he was (is). The team had tried to catch him but to no avail. In fact, neither April nor the turtles had heard from him for a while – and Donatello was getting desperate.

'Come on Dee.' It was that gentle voice that brought Donatello back to the present, and back to Mikey's concerned look that supported his tilting head.

'I think too much' muttered Donatello.

'Some food might make you feel better' said Mikey. Donatello gave a weak smile for he knew his brother was trying his best to cheer him up.

'Oh alright, maybe just one slice' Donatello submitted. He thought it did smell good. A cheerful cry erupted from the door of the laboratory.

'Aww yeah son!' and he tiptoed quickly to Donatello's desk with a 10 inch pizza box in hand. 'It's my own special recipe' he whispered.

'Mikey, I know you like to experiment. What did you use?' Donatello tried to peer into the box, full of curiosity, only for Mikey to slam the box lid down before he could sneak a peek. Certainly smelled good…'Ah ah ah!' Mikey interrupted and held up his hand.

'You have to try it with your eyes closed. You get the full taste and flavour and texture doing that. It's awesome!' There goes the flash of the perfect white grin again... Donatello reluctantly closed his eyes, grabbed a slice from within the box and took a bite. It was just as well his eyes were closed for he could feel them well up, or maybe swell up, he wasn't sure. His tongue was confused with the blend of bitter and sour tastes mixed with a soggy texture that spirted as he bit down. He chewed in a haste to get it down his throat faster and tried hard not to let a mournful noise slip from his mouth. 'It's good, right?' It was that concerned voice again. He could feel those bright blue puppy eyes staring down at him. All Donatello could do was frantically nod and hope even Mikey wouldn't notice his face screwing up. He was pretty sure his brownish green shade of skin had changed colour due to the nausea. 'Dude, you can open your eyes now' Mikey shouted.

'Wha…what did you use?' His words were rather muffled in an effort not to spew whatever it was in his mouth.

'Pepperoni, fish eggs, jalapeno aaaaaaand…oranges!' Donatello scoffed, unsure of how to respond without hurting Mikey's feelings. He tentatively responded, and quietly. 'Why?'

'Well Leo said we needed more fruit, and I thought what would be the best way to eat fruit? And I thought, pizza of course'. Whilst Mikey explained his weird Spock logic (not) Donatello had managed to open his eyes and swallow, although he now regretted taking a bite even more. ' _I wish Leo had never told him to make his own…_ ' thought Donatello. Suddenly he had a ploy. 'You know Mikey', he said confidently, 'I think if Leo wanted you to have more fruit, then _you_ should eat it' and handed over the greasy orange and white slime that was in his hand. 'I can grab something from the freezer.' Mikey recognised Donatello had gone a little sheepish.

'Hey, he's not just moaning at me. He agrees you need to get out more _also_. You hardly go out on patrol with the guys. Come with me - you need to eat' and Mikey almost skipped to the sitting room. Donatello looked back at his desk and sighed once more. 'Maybe I do need a break' he thought, and turned his back on his failures.


	2. Chapter 3

Donatello sulkingly walked over to the middle couch where Mikey had already settled down and turned on the TV. He couldn't figure out what Mikey was watching, but then he didn't really care for his mind kept travelling back to April and the lab. He wasn't sure what to do and couldn't stop worrying about it.

A loud gritty voice announced itself from the main entrance of the lair.

'Hey guys, look who we found on our travels.' Raphael strode into the room with confidence Donatello wished he had. His dark green skin contrasted his red band so perfectly supported by those fierce bright green eyes reflecting his more muscular and heavy form. Raphael was of course accompanied by his two beloved sais that were tucked into his belt. But Donatello's jealousy for confidence quickly turned into something worse. He felt his heart sting the rest of his body from skipping a couple of beats as he saw the familiar blend of orange to red hair; the soft blue eyes and pale but perfect complexion; the yellow top and denim shorts with a star on the behind (not that he had noticed 'blush'). Donatello often wondered what else April wore, especially when he was drifting off at night and thinking through the day's events. Quite frequently April would pop up somewhere, the smell of passion fruit, the feel of her delicate frame from when she offered hugs; the kisses on his cheek. 'TWICE,' he thought, which brought on a smile…However his dreams often turned into nightmares that haunted his beloved REM sleep. The look on her face…the hatred…when she found out it was the turtles' fault that her dad got mutated. For Donatello it was worse than being stabbed by Shredder's blades a thousand times over. He would do almost anything to undo what happened. Donatello hadn't realised he had glazed over until he felt a hard prod almost numbing part of his left arm. He jumped suddenly and turned to face the bright but dark blue eyes of his leader smiling at him, tilting his head to one side with curiosity. Leo was slightly shorter than Donatello and weighed less than his brothers, even though he invested more time in training. Donatello noticed the head of a katana blade peering over his leader's toned shoulder, the hilt wrapped in red fabric and both his metal treasures strapped in by brown straps. All the brothers were supplied with the same leather straps to carry their precious weapons. He hadn't noticed Leo was even talking to him until he refocused.

'Huh?' said Donatello as an automated reply.

'Sigh. It's ok Don, I know you've been working hard. I just said Raph and I didn't find any more canisters but we did bump into April who maaaay wanna talk to you about something.' Leo turned his head away to April who was speaking to Raph. She seemed happy but serious about something.

'Really?' replied Donatello who felt ten times perkier than before his brothers' return. Leo wondered whether Donatello was getting unnecessarily excited by this but let him enjoy his moment. 'Donnie!'

'Oh I love it when she says my name' Donatello thought, with a slight flutter beneath his shell.

'I was spying on some droids to find out what the Kraang were up to' she beamed excitedly.

'April, I said you shouldn't go alone on reconnaissance. At least take one of us with you'. Donatello hated the idea of April being placed in danger, especially when the Kraang were after her (and most probably the Shredder and his henchmen too 'shudder'). 'I know! But listen! The Kraang have found my dad! They've taken him to one of their secret bases – and Baxter Stockman is there too!'

'Oh great, not him again…' moaned Michelangelo whilst having a mouthful of his 'pizza'.

'Why would they work with that weasel?' from an exasperated Raphael.

'Listen, they said Baxter is close to creating a cure, one I know you've been working on.' Donatello looked down and quietly took a breath. April pleaded 'Donnie please, we have to rescue my dad. I don't want anything to happen to him. They're gonna take him to Dimension X!'

'Aww yeah, son, I love dimension X" grinned Mikey.

'Well why didn't you say that sooner?! We need to hurry!' Donatello was almost hysterical at this point.

'Because we think it might be a trap - to get April using her dad as bait!' Leo was standing tall at this point, looking across to April who took an aggressive stance.

'What would you do if it was your father?!' April snapped and stared as if the Shredder himself was across the room, but Leo's eyes burned into her skin until she almost flinched.

'I would not put the rest of my family at risk. We should think this through together.'

April blinked and looked across the room, thinking to herself and suddenly sat down next to Donatello.

'Donnie, please. I cannot lose my father again.' Her pleading blue eyes set his heart on fire as well as turn it to ice. He wanted so desperately to kick Kraang butt, the whole lot of 'em, but how could he ask April to stay behind? He felt uncomfortable rushes of adrenaline course through his heart as he placed his hands delicately on April's. Her hands were soft and warm compared to his.

'April…we'll find your father and bring him home – but I will do everything in my power to make sure you're safe.' He did his best to assure her it would be the case, and it looked like she believed him judging by her long gaze into his chestnut coloured eyes. 'Guys…' Donatello looked across the room and almost surprised his brothers by his assertiveness.

'We need a plan!'


	3. Chapter 4

The purple and orange banded turtles wove their way through the maze of sewer tunnels hoping to find the secret facility soon. Despite it being a similar layout to their home the smell they could tell it was foreign territory. Donatello pursed his lips whilst staring intently at the map he held.

"Ok, April and I managed to find some old building plans of the site for it integrates with part of an old sewage junction where the reservoir pumping station used to be. Raph and Leo should be up top any minute creating a distraction."

'So er, Donnie, why would the Kraang wanna create a cure for mutagen? I thought they were trying to perfect it' asked Michelangelo.

'I'm not really sure, Mikey, but hopefully we can get some intel when we reach the facility.' Donatello looked at his shell cell showing the map of the blueprints and pursed his lips. 'We've gone too far. There should be a tunnel somewhere nearby where the disposal shute used to be. Mikey looked around then looked up at the ceiling of the damp pipe. His brow creased as he tried to focus his sights from where they came from. 'I think it's back there.'

'Where?' Donatello spun round and looked to where Mikey had his sights.

'Up there' said Mikey, pointing at a hidden hole in the ceiling.

'Hehe, thanks Mikey.'

'No worries Dee, just as well I'm here,' he smiled, crossing his hands together hinting for Donatello to help him up the pipe.

Michaelangelo peered through a slit of the cover but the room was dark. He pushed the lid forwards and used ninja stealth mode to slip out and hide. Donatello followed and proceeded to the door with a window of light shining through it. They scouted the 'basement' levels of the facility in case there were any secret projects but, disappointingly for Mikey, there were none.

Donatello suddenly retreated back behind the corner with Michelangelo following suite and peered round the corner. Two Kraang droids no more than 5 feet away. Donatello swung his bow staff at the droid closest to him and Michelangelo threw a shuriken at the other droid's head as the first fell to the floor. Both Kraang who operated the droids then received nasty knocks on the head.

'Quick, hide them in there' said Donatello, pointing to the door behind them.

'Ok – we need to get to the control room. We should be able to find Mr O'Neill if he is being held captive here, maybe even the portal to dimension X if we're really lucky.'

'I think we're getting warmer' said Michaelangelo.

'Phew, it sure is warm in here.' Donatello rolled his eyes at Mikey's remark and proceeded to one of the metal tables laden with papers and scientific equipment similar to his: conical flasks and small test tubes filled with numerous colours.

'Do you think we'll find Mr O'Neil?' questioned Mikey.

'I don't know but hopefully we can find Baxter's notes and schematics somewhere in this laboratory.'

'Do you really think he would label his stuff? The guy seems like a total whackbag'

'Okay now you're sounding like Raph, but touche!' agreed Donatello who looked over to a cabinet with a flicker of angst. There were many canisters containing the familiar green, glowing viscous material they have become to know. Some were broken and any remnants of the mutagen was long gone.

'You did say you needed more to create a retro-mutagen.'

'Hurry and help me find something useful will you?

'Woah Dee, chill…'

Donatello immediately regretted his outburst and sighed. 'I'm sorry, Mikey. It's just I know how much this means to April.'

'I know dude, we'll find Mr O'Neil. That's a promise.'

Michelangelo placed one hand on Donatello's shoulder and then propped himself on the table. He subsequently felt something cold and sticky on his hand and shrieked in surprise.

'Ewww, gross, doesn't feel like prick-stick to me.'

'Come on, we'll check out the back.' Donatello wandered to the back of the room and saw a large glass cabinet, large enough to fit in a person of his size. He pressed a hexagon shaped silver button on a panel in front of the room and heard a mechanical whirring and noticed what looked like an escalator descending into the empty space. The door opened and revealed the similar black hexagon panelling with pink/purple outlines and of course Donatello's new favourite alloy belonging to the Kraang. It looked similar to the cells they had rescued April and Kirby from before.

'Hey Mikey, over here' and gestured for Mikey to come to him.

'Dee, I thought we were staying incognito?' Donatello turned in shock at Mikey's sudden expansion in his vocabulary.

'Hehe,' smiled Mikey, 'been watching too much TV'.

'You know what Mikey that might actually be good for you – in your circumstance. Can you keep an eye out while I scout ahead?'

'You wanna go up alone?' Nah ah' disputed Mikey but Donatello pushed him back once he stepped inside the lift and the door came down - separating the brothers. There must've been a sensor for the whirring noise had started up again, only the lift wasn't escalating. Pink smoke seeped through vents from the top and descended to fill Donatello's lungs. Donatello started to cough and felt his throat start to constrict. He took small breaths to minimise smoke inhalation and pummelled the door in an attempt to force it open. In amidst the panic he hadn't noticed the sounding alarm indicating intruders to the Kraang. Mikey responded to locking the laboratory door and sprinting back to his brother in distress. Bright lights running down the walls started flashing on and off in the space where Donnie was trapped – along with a countdown.


	4. Chapter 5

On one of the upper floors of the second TCRI building, as Leo so badly called it, a silver hexagonal panel dropped on to the floor from the ceiling.

"Great, make an entrance why don't ya?" grunted Raphael.

"I thought that was the idea?!" Leonardo threw back an accusing look and gracefully dropped down to the floor. He swept his right arm outwards to indicate the all clear as Raphael followed suit.

"Ya know, those guards on the roof weren't that guarding," said Raphael, who seemed disappointed it was too easy.

"Heh, I guess we're just that good" grinned Leonardo. Raphael studied his surroundings, noticing the halls were exactly the same as previous secret Kraang bases they had infiltrated.

"They could've changed the décor a little – gets a little boring. How do you think Mikey and Donnie are getting on?"

"Well we've given them the go ahead and I've not heard anything back. Should be ok. C'mon, we need to find some Kraang to bust."

"Likin' your language, bro!" Raphael twirled his sais in excitement – Leo just raised his eyes and gently shook his head. As he turned they spotted 5 Kraang droids ahead.

"Perfect timing!" shouted Raphael.

"It is the ones called 'the turtles'" cried out the front Kraang droid, who had barely enough time to draw its weapon before Raphael plunged one of his sais into its chest. The alien quickly scuttled out of its robotic body and cowardly retreated to a corner. Raphael had a powerful charge and knocked over two more droids whilst dodging their weapons' fire. This distraction allowed Leonardo to slice through the robotic bodies of the remaining two with his katana blades. The crackling of sheared metal and electrics almost covered the sound of approaching footsteps, but not for the turtles. Leonardo twirled his sword and blocked the incoming pulse fire from another droid among a larger group of Kraang droids. They were accompanied by heavy cavalry – two large ape-like bodies with canons coming out of their…ah hem…butts _. Mikey would've laughed at those_ thought Leo.

"This enough of a distraction ya think?" shouted Raphael. Leonardo threw out 3 of his shuriken but only taking out one of the smaller droids by embedding itself in its head. The damaged droid knelt and then collapsed to the floor as the rest of the squad began to fire their weapons. Two of the soldiers didn't have pulse rifles. They had dart guns. The two brothers pushed on hard to avoid the weapons fire whilst attempting to disable the droids. One of the cannon firing enemies had stopped and tried to grab hold of Raphael who was too quick. It stumbled from being unbalanced and Raphael took the opportunity to pull the lumbering Kraang droid over. Leonardo proceeded to attack the smaller reinforcements who were standing as a group. He threw a smoke bomb to the floor that exploded purple smoke to provide cover whilst he twirled round to cut through the Kraang. _Fell for it_ he thought.

However, Leo then felt a prick in his left calf and a flow of dread swept over him as he pulled out the dart. He decided to catch up with Raph and find a safe place in case it was a tranquiliser. As he launched into long strides he realised he was right and suddenly witnessed bright flecks in his vision. Where was Raph? 'I need help' he thought to himself. He continued to push on when suddenly part of his shell caught the wall when going round a corner. He tried to scramble to his feet but the waves of drowsiness hit him as he fell to the floor. His heart stopped a second when he felt a strong arm wrap round his right bicep fearing he would be captured– but relaxed once he turned to face Raph's bright green eyes. Raph had this glow about him whenever he was in battle. That was Leo's last thought before he succumbed to darkness.

Raph rested Leo against the wall and continued to fight back the ever increasing number of Kraang droids. 'They just keep coming. We need to find the others and get out of here.' That small distraction was enough to be darted. Soon he would be like his brother who lay unconscious where Raph had left him. Raph fumed and anger seered through his body and out through his sais as he plunged both metal prongs into the droid that had gotten too close for comfort. It was time to return the favour.

He jumped into a full roundhouse kick to take out the final circle of droids when he suddenly heard the Kraang alarm. Now was the time to move away from the scene of the destruction he'd caused. He pulled Leo into a side room and waited for a large patrol of armed Kraang droids to pass. He released a deep breath he had unknowingly held and knelt next to his blue banded brother who was still passed out on the floor. Raph was confused for he felt more energised fighting the Kraang now than a few minutes ago. Maybe the dart hadn't had the chance to inject the contents into his bloodstream.


	5. Chapter 6

Donatello grasped at the panels inside the machine in hope of finding something to get the door open - or at least stop what was happening. Even through the thick haze of smoke he could see indentations in the wall where some of the panels had been damaged. Some were 8ft up. Something big had been trapped in here before.

'Hold on, I'll see if there's anything on the outside' Mikey's eyes were wide and panicked as he sought to help his brother.

'Mikey, no! Go find Leo, or even Raph to bash down the door. PLEASE don't touch anything.'

'Dee we don't have time. Don't worry, I'll get you out in a jiffy. Umm…how about this?' He swung his arms round and pointed to black conduits running along the floor that connected the bottom of the machine to the wall. Donatello coughed and stumbled as he struggled to press himself up against the window.

'Mikey I don't know what it would do.' Donatello was desperate to get out of the enclosed space but didn't want to resort to drastic measures. The countdown he recognised was increasing in pitch and the lights were becoming so bright he had to shut his eyes to protect them. All of a sudden everything switched off, engulfing him in darkness. He opened his eyes and realised he was crouching.

'Mikey?!' His breath hitched waiting for a reply. There was a large creaking and the door lifted up a little. A rectangular metal object, roughly 12 inches wide, was inserted in the gap which moved upwards a little more. Donatello could hear Mikey struggling and pulled up the door as much as he could with his upper arm strength. Donatello coughed from the sudden movement and quickly ducked under the door to the other side where Mikey was using what looked like a metal plank over a table to act as a lever. Mikey breathed a sigh of relief and hugged his brother.

'Are you ok, bro?' he asked with his hand resting on Donatello's shoulder. He looked concerned.

'Yeah, I think I'm ok. What did you do?'

'I damaged the conduits like you said I shouldn't.' Donatello sighed and bowed his head.

'I had to get you out of there. I couldn't just leave you.' Michaelangelo pulled him back.

'It's ok Mikey, and thanks. Lets grab some mutagen and find the guys.'

'You got it.'

'We should probably get out of here now that they know we're here.'

'Maybe there's another exit to the lab.'

'Lets find out.'

Leo felt groggy when he woke up. He hated tranquilisers and he felt floppy – although he was very pleased to see Raph by his side. 'Hey man, you ok? Cause we gotta move' said the red banded turtle.

'Urgh, I'll be alright' replied Leo as he reached his hand to hold his throbbing head. He hoped holding it would give him some stability. He grabbed his katana blades and hobbled to the window. The coast looked clear but he decided to wait a while for his head to settle.

'What happened?' he said wearily as he sat back down.

'You got darted and passed out. The Kraang sounded the alarm but I don't think it was for us.'

'Donnie and Mikey?!' Leo looked up in alarm.

'Most likely. Come on,' he motioned to Leo, 'we need to find them and get out of here.'

'Do you think they've found Mr O'Neil?'

'Man I hope so…'

Leo peered out of the window again and held the hilts of his swords even tighter in angst of an oncoming attack. Raph followed him outside where they proceeded to find their brothers.

Donatello explored two back rooms for another exit but with no luck. Michelangelo had barged the door with a heavy desk to help prevent the approaching army of Kraang from entering.

'I don't think we have a lot of time.' Panicked Donatello, looking over to Michelangelo who seemed distracted. 'Mikey?'

'Huh?! Oh right, do the Kraang have air ducts?'

'Eh I don't think so, Mikey.' Their search was interrupted by a large thud in the door and weapons firing. Donatello could also hear the distinct sound of metal clashing and approached the door barricaded by his younger brother. All had gone quiet outside as Donatello climbed the table and pressed his head against the door. 'Donnie? Mikey? You in there?' It was Leo, 'thank goodness' thought Donatello. Michelangelo heard his brother's voice and rushed over to remove the barricade.

'Boy am I glad to see you guys' smiled Donatello.

'We need to get out of here before more Kraang show up.' Shouted Leo.

'But we haven't found Mr O'Neil' Donatello retaliated.

'I really don't think he's here, Donnie.'

'Look! This would all have been for nothing if we leave now.'

Leo frowned as he quickly pondered over the situation and looked down the hallway which was still clear of Kraang.

'Alright, but make it quick. How would we know if Kirby was here?'

'I just need to access the Kraang's system. I can plug this into a console' Donatello pulled out a hand held device from his satchel,' and find out if he's here - similar to how we got the rough schematics for the base.'


	6. Chapter 7

The turtles' lair was eerily quiet, just a slight echoing of water dripping in the sewage pipes surrounding the lair could be heard, until…

"Well that was an epic fail!" yelled Raphael as he threw his arms up in the air in frustration. The turtles slowly climbed through the entrance to the lair from where they had parked the shell raiser, where by Raphael proceeded to pulverise his favourite dummy with a mock-up of shredder's helmet on top. Michelangelo sat himself down on the sofa prepping for an overdue video game whilst Donatello and Leonardo begrudgingly entered the lair, with an unconscious April in Donatello's arms.

"Look we found him didn't we?" exclaimed Donatello.

"Umm yeah, but not before he had already escaped!" retaliated Raphael who had decided to redirect his anger on to his purple-banded brother. "You need to get us some reliable intel – AND to keep your girlfriend under control!"

"She is not my girlfriend, Raph!" Donatello tensed his whole body as he placed April on the sofa, stood up and clenched his fists.

"And anyway, Casey was meant to be keeping an eye on her."

"Well that worked, didn't it?! Pretty sure he wasn't working with her on a training exercise in the Kraang facility. Actually, I'm surprised he wasn't with her." Donatello winced. April had once again deliberately placed herself in danger, but she could look after herself, right? After all her powers have saved her and her terrapin friends on numerous occasions. Although Donatello hated the thought of Casey and April spending any amount of time together, he wanted to be sure she was somewhat distracted and out of the way. "I should have known better" he thought.

 _Donatello had searched through the Kraang's online system and had located Mr O'Neill on one of the middle floors. They had reached a large open cavern several metres high where Kirby was hanging from the ceiling, caged. They were shocked to see April already unlocking the cell and setting him free. They couldn't hear what she was saying, but they could tell she was trying to reach Kirby under his wild animalistic self. He suddenly flew out and knocked April off her feet. She fell through the air and dropped on to a metal railing below. Donatello felt bile rise in his throat and desperately tried to run over to her. His brothers however held him back for armed Kraang droids were flying from the upper levels._

" _Guys, get out of here!" April shouted, reaching her arm out towards them. She appeared weak. Everything seemed to happen in slow motion for Donatello as he was almost prised away from the scene of chaos. He fired his grappling hook on to the cage above and swung out of his brothers' grips and on to the metal railing, a few feet from April. Donatello thought he witnessed a smile before she passed out. He picked her up and rang along the metal grates as his brothers defended incoming pulse fires and Kraang soldiers. There were more Kraang descending on them as they frantically sprinted for an exit with Michaelangelo creating a distraction: purple smoke bombs – one of the many useful items to a ninja, or to anyone really._

"Why are you so mad, Raph? We completed the mission, and April is ok." Donatello couldn't convince himself that he wasn't to blame for the failure of the mission, but tried hard to defend himself against the outbursts of his red banded brother.

"Because we could've got our asses handed to us. In our own shells! This was meant to be a "stealth mission" Raph gestured the quotation marks with his fingers. "A lets grab and go mission, as much as I love blowing up Kraang. Right fearless?"

Leonardo sighed and looked down, feeling the disappointment almost get the better of him. It was his fault for he should have made sure April was well out of the way. He scanned his brothers and became a victim of their reflecting disappointment, except Michaelangelo who seemed somewhat distracted in picking one of his palms.

"Well it wasn't all bad - Donnie and Mikey managed to grab some more mutagen – and Kirby is ok. We just don't know where he is. At least the Kraang don't have him anymore. Donnie, see if you can rig up some scanners across the city for any sightings. Let me know if you need help setting them up."

"Already on it" Donatello finished looking over April and ran across the room to his laboratory, wanting to escape Raph's wrath.

"Guys, once Donnie has finished we'll go up top and put the scanners in place. I think we could all do with a run." Leonardo turned to Michelangelo to check he was listening, but the youngest brother was scratching at his hand again.

"Mikey, you with me?" Michelangelo quickly stopped and frantically tried to come up with a suitable answer.

"Err, yeah sure. Just, er, getting ready for…"

"I don't think Donnie will be long. Make it quick, try to set a new record or something. I would prefer to be out of here before Master Splinter gets back from his mantra ventures, whenever that will be." Leonardo decided to retreat to the dojo where he hoped he would be left alone. Raphael watched his older brother carefully walk out of the room and then carried on punching the dummy.

Donatello sat down and pressed his fingers against his temple in an attempt to relieve the increasing pressure in his forehead. _It's just stress_ , he thought, as he dwelled on the events of the day.

 _I need to concentrate. This isn't going to help Karai…why does my head hurt so bad? God, why did I not see? Raph is right, I should have made sure April was safe. But the guys needed me. Who goes there…?_

Donatello swivelled on his chair in angst and saw April standing sheepishly in the doorway.

"Are you ok, D?" April looked with concern.

"Yeah I'm fine, I'm just tired." He wanted to ask what was up but really had no need - he could understand she was anxious about not knowing where her dad was. At least he was out of the tentacles of the Kraang. Swinging his chair back round, Donatello hoped she would pick up on his body language in that he desired to be alone. Unfortunately she didn't.

"Donnie, I'm sorry I jumped in when you asked me not to. But I couldn't just do nothing. Everyone thinks they have to protect me. You guys are like family, and I want to be with you." Donatello's heart froze as he heard the last part. He wished she meant it just for him, but his hope rapidly died as she left the room. As soon as he couldn't hear her footsteps he slammed his fists on his desk, knocking over a conical flask which rolled across the surface and shattered on the floor. He rolled his eyes, hung his head back and groaned in frustration. The chair he sat on was shoved across the room as he went to find some aspirin and a broom from a side cupboard to sweep up the mess.

Later that day Donatello had finished developing new scanners to set up around the city to track Mr O'Neil. He had managed collect some DNA following April's encounter to enable him to track Kirby accurately.

"Okay guys, are we ready to head out?" asked Donatello. He wasn't sure what he was expecting, but it sure wasn't enthusiasm.

"Can you guys go ahead? I'll catch up later." Michaelangelo seemed somewhat lethargic, as opposed to Raphael who was practically buzzing. He had being sparing with Leo in the dojo for a while now and didn't appear to look tired at all.

"Well I'm up for it!" Raphael was already heading for the exit.

"Raph, wait! You need the scanners. That's what we're heading out for. Be patient." Donatello felt exhausted but felt unable to give up the chase. He handed Raphael three scanners and looked to Leonardo who was looking rather flushed from his spa with Raphael.

"You coming Leo?"

"Yeah, I'll be right there. Mikey, come on. If you're not well then go to bed."

"Hey, you're not the boss of me!" Scolded Michaelangelo.

Tension seemed high this evening, although ironically the calmest one seemed to be Raphael who was usually the hothead of the family. _Role reversal much?_ Thought Donatello.

"Fine. Let's go." Sighed Leo, who begrudgingly followed Raphael, then Donatello.

Outside the air was cool and a refreshing feeling for the team, both physically and mentally. For Donatello he hoped it would smooth out the friction between the team. He wanted to isolate himself and proposed that the team split up to cover more ground since they were all tired – except Raphael…

"No worries, Donnie. You got it covered. Leo and I will go eastside." Raphael smiled and cheerfully hopped off a rooftop on to a ledge on the side of the building. He leapt on to the metal staircase on an adjacent building and climbed up with haste. Leonardo shrugged and followed suite. Donatello was now alone, which was how he wanted it to be. He didn't want distractions or anyone telling him that it wasn't his fault. Or anyone to tell him that it was his fault. He sighed and looked down at members of the human public walking along the streets who were completely oblivious to the mutant terrapin presence staring down at them. They all looked to content with their lives.

" _Maybe I could go and see April. I just want to talk to her, and tell her how I feel. But…maybe she'll still be mad at me. What if we don't find Kirby? Will she ever want to see us again? Maybe she's consoling with Casey. That imp. No, I should do everything I can to get her dad back, then she'll forgive me, won't she? *Sigh* Who's behind me now…"_

"BOO!" Donatello almost jumped off the building, with fright or longing desire he wasn't sure.

"Did you miss me?"

"Mikey, you nearly freaked the shell off of me. Why are you out here? I thought you wanted to stay behind?"

"Well, maybe. My hand has been kinda itchy, and it was really bugging me. I thought going on patrol with you guys would keep me distracted."

"We're not on patrol. We're setting up scanners across the city to track April's father."

"Oh right, sorry, I must've missed that part. So, do you wanna grab some pizza?"

Donatello just realised he hadn't eaten anything all day, apart from the gross annihilation of pizza created by Michaelangelo this morning.

"Yeah, why not. Shall we grab some for the others?"

"Or we could just not tell them?" Michaelangelo smirked.

"Mikey?!"

"Okay, okay we'll bring back a doggy bag for them."

"We'll set this scanner on Antonio's, grab dinner and head back. I have work to do when I get back and this headache just will not go away without aspirin." Donatello placed a palm against his head hoping it would somehow dull the pain.

Raphael was finishing placing the last of his allocated scanners high up on a satellite on the Channel 6 building.

"Good thinking there, Leo. Putting Donnie's scanning device high up where we can get extra signal."

"Yeah, thanks Raph." Leonardo didn't feel he should be praised. He was also envious at how perky his hothead of a brother seemed to be. Raphael was contemplating whether or not to address his broody brother when he was alerted to his vibrating shell-cell.

"Hey, it's Donnie. He says he and Mikey are grabbing pizza from Antonio's and taking it back to the lair. I'll race ya" and Raphael immediately sprinted off in the direction of home. Leonardo stood up and felt both of his legs cramping up. He pondered how long he had been sitting on the building's ledge. _I'm in no hurry, he thought. I'm not that hungry._


	7. Chapter 8

Once he returned to the lair, Leo entered the bathroom and closed the door with a sigh of relief. _Some peace_ he thought. Normally a shower after a workout of any kind would suffice but every limb seemed to ache. His calf muscles and thighs in particular felt like they were being stretched. _Maybe a bath would help_ he thought and proceeded to run a mixture of hot and cold water in the tub. Luckily it was slightly larger than one's average sized tub so the turtles could almost submerge themselves underwater. Leonardo removed his pads, wraps and belt and glided from one side of the bath to the other.

'Ooh that feels good' he muttered to himself as he smiled and closed his eyes, feeling the warmth sink in to his over-stretched tendons and muscles. He was slightly annoyed however when he felt the bottom of his shell scratch the bottom of the bath. It seemed to press on a nerve – well, something delicate which made him feel uncomfortable…Maybe that's why he preferred showers. He tentatively peered over his shell and used his fingers to try and inspect what was being intrusively pressed. He worryingly thought he felt something new and hard when the bathroom door suddenly burst open with a bang. Leo scrambled to the side of the bath pressing the front of his shell against the tub with water splashing onto the floor.

'Hey! You can't just come blundering in here without knocking – or even asking' he shouted whilst trying not to blush.

'Sorry Leo,' replied Donatello, 'we need the tub to rinse Mikey' – and on cue Mikey, who's arms were covered in red scratches, was dragged in to the bathroom being restrained by Raph who wore thick yellow gloves – three fingered gloves amazingly.

'Let go of me, Raph. I need to itch dammit!'cursed Mikey who started biting his shoulder in an attempt to stop the itching sensation over-running his body.

'No scratching Mikey. That might be what has caused this thing to spread' ordered Donatello.

'Spread?' said Leo with angst.

'Mikey must've picked something up whilst we were at the Kraang facility. He was complaining of an itchy hand, then when we got back and started eating, he suddenly couldn't stop scratching his arms. Hurry up Leo we need the tub' Donnie motioned him to move as Leo begrudgingly wrapped a towel round himself and walked over to Michaelangelo.

'Wait!' exclaimed Donatello who held up his hands in front of Leo. 'Don't touch him without these' and Donatello pulled out some gloves like Raph's but pink. Leo rolled his eyes, grabbed the gloves and seized Mikey's legs.

'HEY- get off a'me!' Michaelangelo proceeded to kick at Leo who held him strongly in his grip.

Donatelllo proceeded to empty the tub to rinse it out and refill with water.

'3-2-1' counted Leo and the two older brothers placed Mikey in to the bath.

Donatello reassured his brother.

'Don't worry Mikey we won't keep you in here for long. You'll get too cold otherwise.' He reached over for a flask with a transparent but slightly viscous liquid inside and added a few drops to a white flannel which changed to orange. He took a skin sample of Mikey's left arm and placed it in a test tube, whilst Michaelangelo sulked in the bath with his head hanging low, shoulders slumped and knees brought up to his plastron. Donatello began to wipe him over with the flannel.

'Hey Mikey' said Raph as he knelt down next to him and placed a protected hand on his baby brother's shoulder.

'I'm sure it's nothing. It's like when you got shell-acne but without the pustules and explosions.' Mikey looked up at Raph with his glistening bright blue eyes and smiled weakly. Raph suddenly felt bad for he didn't realise Mikey was starting to cry. 'What's wrong with me Raph?' whimpered Mikey. 'Don't worry Mikey, Donnie will fix it.' Mikey seemed to cheer up. He knew he could count on his smarter older brother. He was the smartest guy he knew and could fix anything. Leo stood furthest from the tub, reflecting on the situation but still feeling a little self-conscious from his 'exposure' earlier. _They wouldn't have seen anything, right?_ He thought, in a desperate attempt to reassure himself. 'Leo, you ok?' Leo broke out of his worries and looked at Raph who was curiously staring at him from the tub. 'Yeah, I'm good' replied Leo, although he didn't feel ok. Mikey was in trouble and he wasn't the first to his side – Raph was…In fact he only just realised where he was in the room. He grabbed his pads and dressings and walked out in shame and embarrassment, leaving Donatello and Raph to shrug at each other and scrub Mikey with the diluted wash the scientist had quickly concocted.


	8. Chapter 9

Leo continued to spa on his own in the dojo as part of his daily routine, running through a number of katas from the simple to the complex – even if his mind kept drifting to the events of the Kraang facility inception a few days ago. Mikey had stopped scratching, eventually, with the help of Raph's restraining techniques and Donnie's medicinal wash-down that helped counteract the itching sensation. The youngest brother seemed to be almost back to his normal cheery self. The middle brothers had noticed their leader had kept himself to himself since Mikey's first bad episode of puritis when he had to be forcefully restrained. That's when the cramp in his stomach came back. He knelt with his left arm wrapped around his carapace and propped himself up on one of his katanas. 'Ugh…' he tensed up from the pain in his stomach which just seemed to make the pressure in his lower back worse. 'Maybe I should talk to Donnie' he muttered to himself. He wasn't sure if he had been eating the wrong food which caused him to have this pain that kept occurring – 'more fruit' he said to Mikey. 'Hypocrite!' He thought to himself. Or maybe the cramps were from stress. Sensei was still not back so he was in charge until further notice. _Maybe if I meditate for a while, that might help…_

He sat himself on the floor and crossed his legs, breathing slowly and deeply to relax but

 _That feeling, from the bath, is back_ …

Admittedly he hadn't investigated the uncomfortable sensation due to the embarrassment of his brothers possibly seeing something private last time. Although they didn't actually mention anything to him. There was something pressed against the floor which felt uncomfortable, and it wasn't his shell which made his heart go a little faster than normal – a panicking reaction. He frantically searched across the room, checked the doorway and listened out for his brothers to hear where they were. He was desperate to see what the problem was but at that moment…

'Yo Leo, want some competition other than your ego?' Raph shouted and twirled his sais in excitement.

'Urgh' groaned Leo. Luckily the pain seemed to lessen for the time being.

'Sure why not' he agreed and managed to stand. He didn't want to worry them.

'Mind if we join in?' called a voice from the doorway to the dojo. There stood Donatello with his bow staff proudly held and balanced on his shoulder. A familiar and joyful voice accompanied him.

'Aww yeah, son!' Let's get on it!' Mikey was overjoyed he could finally spa with his brothers. As much as he liked spending time in his room playing video games he wasn't allowed much contact with his brothers in case whatever he had was contagious. He was beginning to get cabin fever when Donatello finally gave him the all clear.

They decided to pair up for their training session; Leo with Mikey and Raph with Donnie.

'Take it easy on me guys. I've not been myself lately' said Mikey.

'Well you've played enough video games to prove it's you' proclaimed Raph who took a defensive stance.

An hour into the session the brothers were well in to their training routine. Michaelangelo threw his right nunchuck forward which Raph dodged and charged Mikey shoulder first. The orange banded brother was perhaps the most agile of the four brothers and quickly avoided Raph's charge and knocked his brother's shell. Raph growled as he steadied himself and spun round throwing his right sai forward which Michaelangelo caught and tugged it from Raphael's grip. Raph quickly spun for a roundhouse kick which Michaelangelo pushed round further and upper cut Raph's jaw – throwing him to the ground. Mikey had hardly let his guard down the entire session. _He's so fast_ thought Raph as he rubbed his jaw.

Donatello was rather enjoying himself, minus a few bright flashes of light in his vision for some unknown reason, for he had managed to contact Leo with his bow staff a few times already. Leo seemed distracted somewhat today. _Ah well, as long as I'm winning_ he thought. _Just_ _this once_.

'Are you taking it easy on me today, Leo? Because you really don't have to' Donatello leapt and twirled his bow staff in to a dangerous and rapid spin. Leo dodged as expected but his body felt heavy and lethargic. He wasn't normally this tired after an hour. An hour was practically a warm up for him. He held on to his katana tightly and pointed the end at Donatello in an attempt to focus on defending himself from his brother's advances. The cramp in his stomach had returned a little while ago but it was tightening from the stress of the training – and he embarrassingly felt like he needed to stop and relieve himself.

'Donnie…can we…just…stop…for a minute?' he puffed.

'But I'm winning!' exclaimed Donatello who proceeded to grind his bow staff against Leo's sword and kicked Leo in the plastron. Leo fell back and dropped his sword and brought his arms to his plastron in an attempt to stem the pain flowing from his stomach. Donatello still had his leg in the air from the kick but quickly dropped his weapon and sprinted to Leo in worry who had rolled over to his right side clutching his front, his neck straining in anguish. Raph had risen from the floor and was wrestling with Mikey when they heard some groans coming from the other side of the dojo. They turned to see Donatello knelt over Leo, shaking him to get a response. They rushed over and Leo was curled up in a tight ball grinding his teeth to stop any disgruntled noises of pain escaping his mouth – but they were pretty audible from his throat.

'Leo, what's wrong? Did I kick you too hard?' Donatello looked concerned and scanned his brother for obvious signs of injury – thinking he had inflicted harm to his brother. _He's had plenty of kicks and never had any major problems_ he thought.

'I…feel…argh!' grimaced Leo as he squeezed his lower body. He felt so embarrassed but he just couldn't contain the pain – and feared possibly something else. That pressure he felt in his lower back was just increasing.

"Let's get him to my lab." Donatello looked at Raph worryingly as he grabbed Leo's upper half followed by Raph who took Leo's lower half and started to carry him to Leo's destination. They made it to the sitting room where Leo suddenly leapt from the grips of his brothers and into the small shallow pool they had. There was an almighty splash and, at first, the brothers couldn't see much, but then they witnessed Leo's body shake and contort on all fours as he screamed. They watched in horror as their brother continued to cry out, grasping at the tiles and dark blue veins almost burned through his skin across his limbs and skull. His whole body tensed and trembled as he arched his back upwards. They daren't take a step for fear it would kill him. Leo's voice seemed to deepen and a horrible cracking noise ripped through the lair and through his lower shell. That was when something emerged from Leo…


	9. Chapter 10

The water surrounding Leo turned from a clear-turquiose colour to a sickening crimson which then rippled as Leo collapsed onto his front. The three brothers stood in horror for a few seconds before they summoned the courage to tend to their brother. Raph ran over to pull him out of the water and turned him on to his shell to get him to breath. He felt sick as Leo was so full of colour from the screaming a few seconds ago during his 'episode' and had now gone a deathly pale green. He breathed in to him a couple of times before a splutter erupted from Leo's mouth. He coughed some droplets of water and breathed quickly to establish oxygen to his lungs. Raph scanned his weakened brother from his head down to the bottom of his shell which now had a new limb hanging between his legs. It was about 2-3feet long and could only be described as a tail. It was darker than Leo's normal skin colour and still had dark fresh blood covering it. Leo rolled his head in confusion at his brothers.

'Mikey, can you get some towels?' asked Donatello who was shocked by the whole thing just like his brothers. He didn't sense any movement from Michaelangelo and turned to see his younger brother just staring at the new limb. Leo's breathing stuttered and his body trembled in shock.

'Mikey! Towels!'

'Oh! Right!' Mikey shook his head and quickly sprinted off. Donatello came over to kneel by Leo's other side.

'Leo, are you ok?'

'Mmmm' murmured Leo, who just shut his eyes and rolled his head back against Raph's plastron, still shaking.

'What…the shell…just happened Don?!' exclaimed Raph.

'I really don't know, Raph. I'm…I'm just as shocked as you are…'Donatello rubbed the back of his head and was dying to inspect Leo's new…growth.

'Leo? Leo, can I take a look?' he peered over Leo's face expecting a response.

'Typical scientist!' spluttered Raphael, forcing Donatello to step back.

'Hey, you have to admit this is fascinating.'

'Our brother passed out and almost died and you call it fascinating?!'

'You're right, I'm sorry. But do you want to know why this happened?' Raph sighed and processed his thoughts to the ground. Donatello was right – how the hell did this happen?

'Might be best to move him somewhere more warm and comfortable.' Raph nodded. Donatello handed him a blanket from the sofa nearby and Raph wrapped up Leo as much as he could. He was certainly heavier than his usual light form as he felt the extra limb thump against his legs every time he took a step. In all honesty he felt rather uncomfortable with the situation but carried on to Donnie's laboratory. Donatello held the door as Raph waddled in with Leo and placed him in a cot on his side. Donatello pushed up a table with a cloth and some cleaning utensils and started to wipe Leo's tail clean. He curiously brushed his fingers over part of the tail and felt scales. It was slowly turning colour to match Leo's natural emerald green but it was still noticeably darker. He inspected Leo's shell where the tail was protruding and a small part had bent upwards forming cracks. _That explains the cracking noise…_ Donatello started to peel away the worst and used strong super glue to fill in the remaining cracks that could fracture more of the shell if not filled. _Now for the interesting bit…_ Donatello turned to Leo's lower shell and pulled a face. Raphael decided it was time to find out where Mikey had disappeared to…After Raphael had left Donatello placed a light scope on his head and turned on the light to inspect. He pushed Leo's legs forwards until he was in a crouching position and leaned forward. There was certainly an opening now substantially larger for where the tail now lay. He guessed they all had small tails tucked away but Leo's for some reason had unexpectedly grown to a substantial size. Again he pulled a face, bit his tongue and placed a hand under Leo's tail. He ran it past the opening for his shell and started to feel around for anything abnormal – not that a giant tail was abnormal…

"Sorry Leo,"he said quietly, hoping for Leo to forgive him when this was all over. He felt something soft which when pressed made Leo clench and twitch. _Well at least that's normal_ he thought and took another deep breath and continued to press around but found nothing else that would require immediate attention.

…

A few hours later Donatello heard a knock at the door. It was Raph who tentatively opened the door once he had the all clear. He walked over to the cot and watched his brother sleeping off the events of the afternoon. He had a drip in his arm which still had remnants of the blue veins that stuck out during his… _growth spurt?_ If that's what you call it.

'Raph I have no idea what happened. Something must have triggered this in the past few days.' Donatello spun round on his wheely desk chair with his head facing the ceiling, pondering over his thoughts and theories. Raph looked down at the floor.

'Think I might know. He was darted at the base and passed out for a few minutes. I thought it was just a dart to knock you out, but…maybe there was something else inside.'

'Well it's the only thing I can correlate against what has happened. Unless we suddenly start sprouting tails I guess we'll put it down to that.'

'You guess?! How the hell can you guess? You're a scientist, you know the answers. How can you just guess?!' Donatello just felt lost. His head hurt and he'd been feeling woozy for a few hours. Maybe from the stress of Leo's incident and looking at the screen too long but normally the latter didn't bother him. Guess he needed some rest…An exasperated Raph turned back to the cot and leaned on a table nearby.

'Is he gonna be ok?' Donatello looked round.

'I've checked him over and he seems to be ok. Vitals are good, temperature is back to normal. I've attached a catheter for some pain killer and an IV for hydration so he should be alright. As long as nothing else happens…'

Raph glared at his purple-banded brother with a questioning and threatening look – as in _are you being serious? If yes, then I'll kill you_.

'I've done all I can. He just needs to rest, and you should probably too.' Raph refused to budge.

'Raph, it's okay. Can you see if Mikey is okay and let him know Leo's recovering? I've got this' Donatello placed his hand on Raphael's shoulder who shrugged it off and strode to the exit. While Leonardo slept, Donatello decided to look over Mikey's skin sample results once again. A strange agent seemed to be mixed in with sebum – when Mikey sweats – which for some reason makes his skin turn sore like an allergic reaction. He needed something to counteract it otherwise Mikey would go crazy – well, more crazy. There was only so much washing they could do, which Mikey could now do himself. He had established it wasn't contagious and could be controlled for the time being, but if this was the result from Kraang technology, just like Leo's…condition, then what could happen? He turned to Leo and saw him still sleeping. His tail had started twitching which was a good sign _I think_. _Mikey wasn't injected, how did he pick this up?_ He suddenly pictured himself back at the base in the lab. He was browsing Stockman's notes (if that's what you called them) and…He remembered talking to Mikey about not finding a cure and being in that room. The lights and smoke. Donatello started to panic and tried to think of when Mikey had rescued him. He was no longer trapped, safe with his baby brother. Then his older brothers found them.

 _So when did Mikey contract the puritis?_ Donatello pondered.

 _When Mikey first came to him in his lab it was his hand that was itching. He had touched something._ 'The stuff that wasn't prick-stick on the table!' he said out loud. _Now what's the pH on this, I wonder_ thought Donatello. _It must have seeped through his skin and now it's playing havoc with his sebaceous glands. I need to conduct more tests. I feel so tired…_

… _._

Raph exited Donatello's lab and walked over to the couch infront of the TV. Michaelangelo was already sitting there, staring blankly at some cartoon channel that Raphael normally disliked. It had been a few hours since Leo's ordeal and it didn't look like his youngest brother had slept a wink. Raph sat down next to him and twiddled his outer fingers.

'You wanna watch something or…' he never finished his sentence for Michaelangelo suddenly flung himself onto his brother wrapping his arms tightly around him.

'Is Leo gonna be ok?' He asked quietly and sombrely.

'Donnie is looking after him. He's already recovering so he should be good.'

Michaelangelo looked doubtful and never looked up at his brother. Raph scanned over his brother and noticed he had some skin peeling on his shoulders. He brushed it off and noticed there was more on his arms.

'Mikey, I think we should go see Donnie to check over your skin. I think the rub-it-on stuff is drying it out.'

'Okay,' sighed Mikey and rolled off Raph's lap on to the floor with a flump. Raph couldn't help but smirk.

…..

Although Donatello was in the middle of a nap he felt a disturbance in the perfect balance of his laboratory. He stirred to see Michaelangelo and Raphael walk together towards his desk.

'Hmmm just the turtle I wanted to see' stretching, yawning and speaking simultaneously.

'Yeah, I think the stuff you're giving him is drying out his skin.' Raph ushered Michaelengelo to sit on the seat next to Don.

Donatello inspected his younger brother's arms and took another skin sample for testing. His hands were the same, no worse despite one of them being the initial contact with the foreign substance. He turned round to pull out a few petri dishes and rubbed the sample on all of them. He then tried adding a number of different solutions to each one, making notes and observations in his A5 notebook with numerous scrawlings indecipherable to his brothers.

'Well?' questioned Raph after about 15 minutes of silence. Donatello turned back round.

 _Gosh he looks tired_ thought Raphael.

'I'd rather not try anything until I get some results from these test trials just in case something doesn't work the way it should. Plenty of fluids for the time being, Mikey – and try to get some rest, okay?'Michaelangelo was disappointed for he had been trying to 'get some rest' all evening. His mind kept glossing over what had happened to his elder brother. His leader was normally so calm and controlled and then he just completely flipped; sprawled out in front of his brothers who were helpless; the foreign body that emerged out of his shell; the blood; and then nearly losing his brother – our leader. Michaelangelo tried to shrug off the thought – unsuccessfully. Raphael escorted the youngest to his room as Donatello patiently waited for the test results. He thought about doing some scans on Leo's lower half to see what was happening but he had a horrible headache which the painkillers didn't assist with.

…

Donatello didn't remember dropping off but when he woke up he heard some metal clanging on the floor. He quickly stirred and saw Leonardo was waving one of his arms around hitting the metal container on the table with Don's utensils rattling around inside. The leader still had his eyes closed. Donatello thought he should try to wake him to see if he was ok. Well, as well as he could be under present circumstances. He walked over and sat on the side of Leo's cot, only just fitting on the bed with the extra limb taking up space. He shook Leo and gently spoke his name. Leo didn't react to start with but with an increase in audio volume he started to stir. He pried his eyes open a little and then squeezed them shut as his face creased. His body arched and then turned to his left side squeezing in to a ball. Donatello could hear him groaning in pain.

'Leo? Leo, come on talk to me. I'm going to up the dose to help with the pain, okay?' Donatello went to the other side where the IV bags had been placed on a stand and slid a switch a little. He kneeled down and tried to get Leo to look at him but to avail. He took Leo's hand which was clamped in a tight fist and prized it open to hold it. Leonardo squeezed tightly and shuddered out a deep breath. Donatello heard a whimper from his older brother.

'Make it stop' he begged quietly, still curled up in a ball.

'It will take a couple of minutes for the painkillers to kick in.' Leonardo's breathing quickened as he attempted to deal with the waves of pain that erupted from his lower back and from something else that he had never felt before.

'AH, shell...Agh…it hurts!' cried Leo. Donatello looked over to Leo's tail which seemed to have grown roughly three more inches in the past few hours. Leo threw his head back against the pillow and breathed in and out. Donatello responded by rubbing the upper part of Leo's shell to relax him. It was always something Leo used to do to the others, especially Mikey when he had nightmares. Don thought of Raph doing the same for Mikey at that moment since Leo wasn't around. Don was brought out of thoughts by another disturbing crack from the lower end of the bed and another groan from his brother. He peered down and noticed a bit more of Leo's shell had split, including the parts that had been glued together. He wondered how long and wide this tail was going to become. It was going to be a long night…


	10. Chapter 11

Donatello finally emerged from his laboratory around midday the following day, looking exhausted and unsteady on his feet. Raphael immediately leapt off the sofa to come to his purple banded brother's aid.

"You ok Donnie? How's Leo?" said Raphael, expressing concern.

"Leo is resting up, dosed up on painkillers. His tail has grown longer overnight, and his skin appears to be darkening. I've been running some blood tests and it looks like Leo has been infected by a substance that's changing his physical anatomy. Most definitely from that dart you mentioned. I'm not sure how far this will go." Raphael had no words. He was the one in charge whilst Leo was out of action and he had no idea what to do, or say.

"Can you fix this?!" he exclaimed.

"Well, I would like to run some tests on you and Mikey if that's ok. After all, you were darted, and unfortunately Mikey's skin irritation is running rampant over most of his body now. He may still be having an allergic reaction to whatever was in that substance. I don't really want to give him steroids unless I really have to. Ideally I would need a sample of what was in that dart, but I admit it would be too dangerous to go back to the facility. How are you feeling anyway?"

Raphael was struck by the question. In his mind he felt fine. Other than the fact he hadn't slept all night as he was keeping watch over Mikey and trying to peek in on his two other brothers now and then.

"Donnie, I feel fine. Don't worry about me. You should be worrying about Mikey and Leo. They need you. I need you."

Donatello was quite taken aback by Raphael's confession.

"Thanks Raph, but just to be safe, please can I do these tests?" Raphael sighed, but nodded.

The two brothers walked in to the lab; printouts of tests results and documents splayed out across two different tables, one that used to be Donatello's less chaotic work space. If Raphael looked at any of them they may as well be written in a different language. As soon as he entered the room he scanned the vicinity for his older brother. His heart rose to his throat as he saw an almost unrecognisable form lying limply in a cot in a corner of the room. Raphael instinctively raced over to his brother's side and froze. Instead of an emerald colour, Leonardo's skin had darkened somewhat to a dark forest shade of green, matching his newly emerged tail. It was overhanging the side of the bed as well as two IV bags helping to supplement his brother's weakened body.

 _How could I let this happen?_ Raphael was drifting through his self-punishing thoughts when Donatello interrupted him.

"Raph?"

"Hmm?"

"Could you come over here please?" Raph did not want to move, fearing his beloved leader would slip away if he took even one step back.

"Raph." Raphael swallowed and reluctantly turned towards Donatello. He took a seat and hunched over glumly as Donatello extracted a vial of blood from Raphael.

After a rather long half hour waiting for the sample to be processed in a centrifuge and analysed on Donatello's computer, the scientist reported back.

"You have abnormally high levels of cortisol. I would blame it on recent events as it does normally result from stress, however I am concerned that this could be a result of being darted. How have you been feeling? Any pain, nausea, dizziness?"

"You asked me that already." Donatello pulled a face.

Raphael looked away, trying to think before he spoke (which was unusual for him).

"Donnie, really, I feel fine. Just worried about the guys." Donatello screwed up his face – he was unconvinced.

"Okay, okay. I maaaay not have been sleeping that much over the past few days. When I sat with Mikey last night I thought I was gonna drift off, but I didn't. I didn't even feel sleepy. I kept thinking…"

"I could administer some artificial melatonin to help you get to sleep. It will hopefully help the body to realise that it needs to rest."

"Maybe you should give some to Mikey to calm him down. He was pretty upset last night."

"It's not a sedative, Raph, just something to help you get some REM sleep."

"And what about you, Donnie? Are you ok? You look like you could use some of that melstuff as well." Donatello shrugged and turned away.

"I have a lot to figure out, Raph."

"We need you to fix this, Donnie. You're the only one that can."

"I…I don't know if I can." Donatello almost succumbed to the onslaught of guilt but battled through the tears threatening to tread down his face.

"I know this is not a good idea, but we need to go back to the facility. If I can find those samples the Kraang hit us with, maybe that will give us some answers."

"I can't let you go alone, Raph. Can we at least wait until Leo is conscious before we make any rash decisions?"

"Donnie, we don't know when that will be. Why do you always support Leo over the rest of us? Like you said, we don't know what's gonna happen, which is why we need to find the answers now! I suggest you stay here with Leo, whilst Mikey and I head up top."

"I can't let you do that, Raph." Donatello took a defensive stance as he prepared to reach for his bow staff.

"Seriously, are we gonna fight over this?"

"Yes, we are. I am trying to save our family, and I don't need a self-destructive influence to sabotage my efforts."

Raphael was exasperated - the first time he had felt this way for the past few days. He felt good to let go; he grabbed his sais and launched himself at Donatello who predictably blocked his attack. Although he placed his full weight forward, he felt himself beginning to slide backwards - friction wasn't on his side. Raphael pushed him away and composed himself for a second launch. Donatello flipped back over his desk which the red banded brother collided in to. Passion was on Raphael's side, but unfortunately for Donatello so was anger. He leapt over the desk in pursuit and kicked behind his younger brother's knees, causing them to buckle and give way. He pinned down his victim and forced his forearm against Donatello's neck. Bright green eyes met the sadness and fright of brown, however their glares were not interrupted despite the sudden and excited outburst from their youngest brother.

"Yo Donnie, Raph, come look at me, woohoohoo!"

* **Author's note** * - thank you for your support so far, especially as this is my first story. Special mention of Yukio87 for your enthusiasm and support and the guest who left the review =)


	11. Chapter 12

Within the second TCRI building the Kraang seemed somewhat pensive. Droids were patrolling the corridors in groups of 8-10, all armed with pulse rifle like weapons. One silver droid separated itself from the rest of the group as it entered a side room, whilst the rest of the droids stood outside guarding the entrance. Inside there was a spherical control panel being operated by a blue Kraang, the silver droid's leader, who then demanded a report.

"Report Kraang, where is that which is known as species 579?"

"Kraang has been unable to locate and recapture that which is known as species 579."

"Kraang must keep looking. The scientist known as Baxter Stockman requires his alpha specimen so that he may proceed in building a mutant army. Species 579 was to be terminated, deemed too dangerous for Kraang to control, but managed to escape. Kraang is incompetent. We must find and destroy this creature. We have the samples that we require."

The lead Kraang droid noticed the other had gone quiet.

"Kraang, confirm we have the samples that we require for Baxter Stockman."

"The samples Kraang extracted from Species 579 were due to be administered in to April O'Neil's paternal subject. These were regrettably fired at the turtles during our last encounter. In self-defence." If Kraang could look sheepish it would certainly show at this point. The lead Kraang droid flipped.

"This is an incalculable error. We must locate and retrieve specimen 579, and the one known as Mr O'Neil, and the turtles."

"We have received intel that the turtles have placed beacons around the city. If Kraang can tap in to the unique frequency of these beacons, we can track Mr O'Neil, who will then lead us to the turtles. More specimens for Baxter Stockman."

The lead Kraang pondered this for a moment.

"Proceed in hacking the beacons, and track Mr O'Neil. Continue your search for species 579. He must be found and terminated, along with any other specimens along the way."

...

At first, Raphael refused to release Donatello, but then curiosity got the better of him - knowing Mikey he was probably up to mischief. Raphael never broke eye contact with Donatello as he slowly rose from the floor. His rather shocked younger brother quickly scrambled to his feet and retreated towards the door, never turning his back to his hothead of a brother.

"Guys, come here!" Mikey sounded very excited.

Donatello hoped by some miracle that Leonardo had woken up and Michelangelo was excited to see him conscious, however he knew this was improbable. He cautiously turned towards his leader who was still lying lifelessly on the cot, completely unaware of the current conflict between his two immediate younger brothers. He needed Leo right now to take control. Raphael was the strongest of them all, but at least Leo could possibly talk some sense in to him.

" _What am I thinking, there is no way of talking Raph in to any sense. Maybe I could try injecting him with the melatonin,"_ thought Donatello.

" _That way at least he won't try to leave."_

Raphael mirrored Donatello's movements as he also cautiously moved across the laboratory towards the door. Luckily he had now placed his sais back in his belt, although for Donatello he felt like had already been stabbed - by the look of fury in those fiery green eyes. Both brothers peered round the doorframe in angst. There was no sign of their cheeky younger brother in the living room which fortunately seemed intact. Donatello noticed the walls had a particular shine to them in places but then blamed his dodgy vision on lack of sleep. They wondered if their youngest had shouted from his room.

"Guys, up here!" The two brothers responded and looked up at the ceiling - where Michelangelo was on all fours, upside-down!

"Mikey! How the hell did you get up there?" Shouted Raph.

"Get down from there before you hurt yourself!"

"Guys, this is so cool. I'm like Spiderman dudes. I can climb walls, walk on ceilings. This is awesome!"

"Mikey, I understand your excitement but how the hell has this happened? A few days ago you couldn't stop scratching and you were locked up in your room. Now you're climbing walls. What do you think will happen in a few more days? Maybe you'll grow a brain, who knows!" Donatello was quickly becoming vexed.

"You know, Mikey would be awesome at sneaking in to the Kraang base. They wouldn't think to look up. No one does."

"Raph, not this again. We are not going back there, not until we have control of this situation and that Leo is awake to agree with me."

"Wait, why are going back to the Kraang base?" Michelangelo queried.

"We are NOT going back to the Kraang lab." Donatello sighed. He wasn't sure why he was going to proceed in explaining.

"I need samples to examine in order to find an antidote for your skin condition, Mikey, and to find out some answers regarding Leo's condition, and possibly Raph's."

"Whoa, whoa whoa, Dee. What do you mean, find an antidote? This is something I can contribute to the team, dude. Don't take this away from me!"

"I agree with Mikey."

Michelangelo was taken aback that his hotheaded brother agreed with him for once.

"You know what, fine! Go ahead. No one listens to me anyway, then everyone always expects me to fix everything when it all goes wrong."

"You know what Donnie, if you hadn't followed your girlfriend's orders in rescuing her dad, then we wouldn't be in this position. You wouldn't have to, as you say, fix everything. But shell fer brains we need to take action now. We can kick some serious Kraang butt with Mikey's new stealth mode in action. We would make a great team."

Donatello had nothing to say as he was busy pondering what could have happened had he said no to the mission in the first place. Although Michelangelo wouldn't have his new "power" as he calls it, Leonardo wouldn't have suffered a practically life changing mutation. Raphael would probably still be an angry hothead with no respect for authority or for the wishes of his brothers so no change there. He resolved his inner turmoil for the time being by returning to his safe haven – his laboratory. Raphael huffed.

"I guess we have the go ahead, Let's go, Mikey."

"Awww yeah, the new A-TEAM is a go! Booyakasha!" Michelangelo threw his fist up (or down) in the air and leapt on to the floor. Unfortunately as he started to make his way out he kept sticking to the floor so his speed was slow at first as he adapted. He eagerly followed Raphael who reviewed the lair once they reached the exit. He then noticed shiny webbing type substance in different places around the living room where Mikey had been messing around with his new found power. He eagerly hoped that Leonardo and Donatello would magically appear and join them on their quest, but that was not to be.

...

Donatello closed the laboratory door and drew up a chair by Leonardo's cot. He tried to monitor the blue banded brother's breathing but proceeded in glazing over, dwelling over the day's events. He felt exhausted. He leaned on the side of the cot and held his brother's closest hand.

"Leo, if you can hear me, please wake up. Shell, you are missing out on all the fun." Donatello smiled weakly.

"Raph and I had a fight, no surprise there; Mikey has turned in to Spiderturtle, that's a new one. I bet he'll come up with a cringe worthy name for himself; you have a tail which I don't think you even realise; April hasn't come back, and neither has Splinter." Donatello looked at his shell cell – no missed messages or calls. He wasn't sure if he even wanted anyone to contact him, fearing it would be more bad news. Whether it would be Raph/Mikey calling for backup or even April finally confessing that she did not have feelings for Donatello. It was a demeaning thought that came across Donatello's mind often, sometimes in the form of a nightmare, one that he never shared with anyone.

"Should I have said no? Should we not have gone ahead with the rescue mission? I followed my gut instinct, Leo. How can I or anyone ignore that feeling? I knew it was risky. You knew it was risky. Everything is just a mess, and I don't know how to fix this." He stared sadly down at Leo's tail.

"You never know, maybe you'll enjoy your new limb and appearance. We are ninjas after all, we can adapt. Mikey certainly seems to have accepted his change. Please wake up. Tell me what to do. I promise I will do everything in my power to fix this, but I need you to wake up." Leonardo didn't stir despite Donatello's plea.

"That's okay. I understand. You need to rest." Donatello took a deep breath, finally giving in to the darkness and drifted off.

...

Leonardo's POV

Leonardo had no intention of opening his heavy eyelids, however he felt a presence that disturbed his sleep. Begrudgingly, his eyes slowly opened.

 _Urgh, why do I feel woozy? Why is it so bright in here? I don't feel right. Shell, it feels like my insides have ripped out and put back in again. Why is my arm numb? Oh, hi Donnie. I see you fell asleep in your lab again. Nice to see you're keeping me company while I sleep in your lab. Wait, why am I here? So many questions, I wonder where Mikey and Raph are. I can't hear anything, hope they're ok. I should find them._

 _Ow! Why does it hurt when I try to move? Wait, what the SHELL is that? I look like Leatherhead! What's up with my arms, and what's up with this tube in my arm? Get it out!_

 _Donnie, get this thing out of me! Donnie, can you hear me? Donnie, wake up! WAKE UP!_

 _..._

* **Author's note*** – by the way, in an earlier chapter I wrote catheter when I meant cannula – two COMPLETELY different things, haha! Leo does not have anything up his woohoo! I already have the next chapter up and running but want to finalise things. Unfortunately for Donnie, Leo wakes up...


	12. Chapter 13

Donatello thought he felt his bed stir. It was now uncomfortable as it was suddenly fidgeting underneath him. He managed to pry his eyes open long enough to spot that his older brother was trying to get his attention. He looked terrified. Donatello's brain suddenly acknowledged that his brother was finally awake and kicked itself in to action.

"Leo?! Are you ok? Calm down. It's going to be alright." Donatello rubbed one of Leonardo's arms in an attempt to comfort him somewhat since Leonardo seemed to be panicking but not saying anything. He frantically clawed at the cannula in his arm; his breathing quickened as he removed the invasive tubing and held his arm to stop the bleeding. He started shuddering with each quick breath he took.

"Leo, please, you can't remove that yet. You need those supplements. Your body has been through a lot lately." Leonardo didn't seem to be listening and suddenly froze in motion. He slowly turned his frantic gaze to his new tail – and just stared at it. Donatello didn't want to know what was running through his brother's head right now but he could imagine the sort of questions Leonardo wanted answering.

"Leo, I can't imagine what you're feeling right now, but I'll try to answer some questions you probably have." Leonardo remained unresponsive, completely submerged in his confused mental state.

"When you were darted, you were injected with a chemical agent that induced mutagenesis. Unfortunately looking at the DNA I have analysed so far, it is not entirely yours. It looks like it contains traces of a sample that has been taken from a lizard, not sure what species yet. Hence the tail and the weird scale-like appearance on your skin. But…you may develop other characteristics, maybe self-healing properties – which would be cool. I'm going to monitor you closely for a while. Hopefully Mikey and Raph will get back soon with those samples, although I don't know if they will be the right ones. Are you getting any of this?"

Leonardo's eyes slowly blinked as he looked up menacingly, staring intensely into his brother's. They looked glazed but determined at the same time. His bright blue eyes were now a hazy grey. Donatello shivered. It was like someone else was looking at him. The leader's body still hadn't moved an inch since he looked down at himself, and he didn't appear to be breathing which frightened Donatello more than the ongoing glare that he had.

Donatello worryingly took a step back, watching as Leonardo slowly placed both arms on each side of the cot who then carefully shifted his body so that both feet touched on the ground, without taking his eyes off his younger brother. He was now standing unaided with both shoulders pulled back and he tilted his head forward to one side, as if he was analysing a target. Donatello froze, not knowing whether to move or not, fearing Leonardo would suddenly launch himself at him.

 _But why would he? He was his brother. Leo wouldn't harm anyone, right?_ Donatello thought. He also wondered if Leo had grown a bit taller. He seemed to be more of his own height.

Leonardo's tail started swinging dangerously from side to side, just missing impact on the metal table. It was now long enough to scuff the ground. His feet twitched but hesitated to move, as if trying to decide whether to take a step or not. Donatello thought this would be his chance to reach for a sedative, which was unfortunately behind his brother who seemed to be in a delusional and unpredictable state.

"Leo, it's Donnie. Remember? I'm your brother. Do you not recognise me?" Leonardo took a step forward but stumbled and had to stabilise himself against a nearby table. Once he regained his balance he shifted sideways to get closer to Donatello, but kept his hands propped against the steady surface – still staring. Donatello now noticed that the ends of Leo's fingers had claws emerging, scratching the metal in contact.

"You're not yourself, Leo. You've been infected by different DNA which is messing with your head (I hope). Come back to me, Leo. You would never hurt me. Look." Donatello held his hands up, showing that he was unarmed. Once again Leonardo tilted his head to one side to inspect Donatello's vulnerable form. He stepped away from the table and cautiously walked forwards with more ease. He looked as though he was quickly gaining control and balance with his new limb. As Donatello also stepped back from the table towards Leo's cot, he noticed spots of blood on the floor; a trail led from the bed to where Leonardo was currently standing. He felt his heart rise another inch.

"Leo, I'm sorry, but you need to rest. You're still bleeding. I can fix you up, but I need you to trust me. We're brothers. That's what brothers do, we help each other. We trust each other, right?" Leonardo's face turned from focus to confusion, and then in to a grimace as he doubled over. Once again his body contorted with the addition of his tail attempting to wrap around his body, only now he had lost control over it.

Donatello seized his chance to grab the sedative and inject it in to Leo's arm just before he was knocked out of the way, falling with a heavy thump. Leonardo responded angrily - crying out and attempting to crawl along the floor with the aim to seek vengeance on the one who injected him, but the sedative and his lack of energy summoned him into unconsciousness.

Donatello froze in his current position for a few seconds and released a long deep breath.

He begged for Raph and Mikey to come back ASAP.


	13. Chapter 14

*Author's note* - I'm sorry for the delay in updates. Just a heads up, this chapter takes a weird turn in the second half (there is a reason for it), so I apologise in advance if anyone is offended by the content. This has been upgraded to an M story.

...

Raphael decided to check one of Donatello's tracking devices since it was on the way to the Kraang facility. So far they had not yet received any alerts that Kirby had been sighted. He was quickly swaying to the side of giving up hope on April's father. Kirby just seemed to be riddled with bad luck. First he and his family were tormented by the Kraang at their summer house when April was a little girl, including the abduction of April's mother. Next his daughter met giant talking ninja turtles who then dropped Kraang mutagen on him. As a consequence he was now being chased by their alien enemy and isolated from his remaining family. Raphael stared down at the ground with a glum expression on his face - Michaelangelo cautiously approached him and placed a hand on his shoulder.

"You ok, bro? You seem a little down?"

"I'm fine. Let's just get goin'." He shrugged off Michaelangelo's comforting palm and raced towards the TCRI building. The wind was suddenly knocked out of him as a hard invisible force struck him across the middle of his plastron. He slammed into the wall behind him and rubbed his head to clear his sight. His insides throbbed from the impact on both front and back. Luckily his shell took the brunt of the wall.

" _You shouldn't be out in the open. The Kraang might find ya."_

Raphael couldn't tell where the dark, husky voice was coming from, but he wanted to find out. He took out his sais and quickly took a defensive stance. Michaelangelo rushed over with nunchucks at the ready.

"Who goes there? Show yourself!" Raphael quickly scanned the area for the unknown presence.

" _Haha, and why would I do that? How do I know you won't attack should I reveal myself?"_

"We can't trust you if you hide from us, dude" Michaelangelo intervened, but nothing stirred.

"What do ya want? Show yourself." Raphael was becoming increasingly agitated. He cautiously surveyed the building and peered round corners for the hidden entity.

" _Just to warn ya. The Kraang have hacked your brother's scanners. They'll find you, soon."_

"And why do you care?"

" _Once they find you, they'll focus all their sights on me."_

"Well, looks like they have a common enemy."

"Hey, invisi-guy why don't we try to talk this out? You know, where we can put a name to a face."

Michaelangelo glanced at his brother who looked pensive.

In front of them an air conditioning unit suddenly bent inward as a heavy weight clambered down. It was a similar height and shape as the Newtralizer, however the broad creature had bright green speckles across its black scaly body and limbs. Despite his darkened skin, the turtles could see lighter areas of healing wounds and scars. If Donatello were there he could tell them some were from incisions. His dark eyes reflected the colour of the night sky, and he had a snake-like tongue that tasted the air every now and again.

"So, what have you got against the Kraang? Did they change you in to a mutant?"

"Once they changed me in to this form, they locked me away in one of their laboratories. I endured vigorous training exercises and torturous scientific experiments for years. They wanted to break me. To give up the will to fight for myself. To obey their orders and help lead their mutant army, and to destroy human life on this planet. I, on the other hand, had other ideas." The mutant clawed against the closest wall and gritted his pointed teeth.

"If it wasn't for you turtles, I wouldn't have escaped this quickly. Your brother, Donatello, unknowingly released me. But I must warn you, stay out of the way."

"We can't do that. We have to infiltrate the facility and retrieve some tech that we need."

"If you hate the Kraang as much as we do, why don't you help us?" Michaelangelo was always the diplomatic one.

"As I said, I have other ideas." The salamandrian type creature turned and leapt over the ledge of the roof.

"Should we follow him?"

"I don't know, Mikey. We don't know anything 'bout this guy really."

"Do you think it's true? What he said about the beacons?"

"We should probably head back and check." Raphael acknowledged that they should probably head back to consult Donnie - begrudgingly. He was eager for Mikey to try out his new stealth skills and use to their advantage.

"Why don't we just call them? We've got our T-phones."

"Nah, Donnie will probably be worrying." Raphael backtracked even further to guilt – for leaving Donnie on his own with Leo, and for dragging Mikey out on their dangerous venture. He knew the scientist would be fretting.

"I'll race ya."

...

Leonardo slowly stirred, feeling an ache in his bicep from the injection site.

"Donnie?" His voice sounded weak and whispered.

He realised he was on the floor which felt too cold against his skin, forcing him to get on his feet. He felt abnormally off balance and clung on to a nearby table for support.

"Donnie?!" He spoke a little louder this time, but there was still no answer.

" _Where is everyone?"_ He thought to himself.

Leonardo took each step with care as he approached the sitting room. He noticed the strange webbing substance on parts of the walls and floor and took every caution to avoid contacting it as he explored the lair. He peered round the dojo and found no one there, not even Sensei.

" _How long was I out? Where is everyone?"_

As the blue banded brother inspected the bedrooms, he thought the idea of a hot bath was most welcoming. He felt clammy and wanted to wash himself down.

As he ran the hot water he quickly stripped off his wrappings and bandana. Someone had already removed his belt. He peered in to the mirror to inspect the new scale-like appearance on the sides of his face, pressing his fingertips against his skin to make the affected areas larger for him to look at. However he suddenly flinched back as his claws pricked his skin. There was no harm done, just light indentations.

He stepped over the bath ledge and knelt down as he was unable to submerge his entire tail under the water whilst sitting. Standing upright on his knees, he started to lather himself down with the warm water and shower gel. It was a refreshing and comforting feeling. A little too comforting, almost… pleasurable…

He closed his eyes and started rubbing his flexed upper arms, appreciating the soothing motion rolling up and down his stiff toned muscles. His hands spread to his upper plastron which quickly moved on to his lower body; his elongated tail tucked under his body between his thighs as he gracefully slid backwards against the side of the bath, the hot water encompassing him. He basked in the warmth. Once again his muscles felt over stretched, but he was pleasantly distracted - on the rushes of adrenaline and satisfaction that ran through his body as he felt along the length of his tail. He rubbed slowly and deeply in circular motions and unconsciously moaned, especially when he reached upwards along his smooth inner thighs. His heartbeat quickened and his breathing deepened, soaking in this feeling he had never experienced before. He wanted more as he caressed an opening beneath his carapace near the base of his tail. As a rush feeling travelled down his body to his lower region he tipped his head back and groaned again. Both excitement and nervousness coursed through him as he began to press inward.

 _This feels so wrong. I want more…_

Leo grabbed hold on the side of the bath as he began to writhe from the overwhelming sensation of pleasure erupting inside him. A moan escaped his lips as his muscles clamped down and tightened round his finger, welcoming the new intrusion. His knees spread apart as much as possible to open himself up further, gasping at the extra width of finger as he pushed in deeper.

"Umm, Leo? What are you doing?"

Leonardo froze, as did the blood in his veins. He hadn't locked the door in case he needed help. In his peripheral vision he could see his tallest brother, Donnie.

 _What the shell am I doing…_


	14. Chapter 15

Donatello sat at the kitchen table, clutching a hot cup of coffee he had reheated in the microwave. He wasn't quite sure if he was dreaming or if this was all real. Everything was very much out of place. All he needed now was for April to ask him out on a date and that would be the cherry on top of the icing. He glanced up as he heard tentative footsteps outside the room. Leo tried his best not to look directly at him with his sheepish and forlorn expression as he dragged a seat to the table. He tried to sit town at the opposite side away from Donatello, however he struggled to get comfortable with his extra limb to contend with. Once he remained still for a few seconds, it dawned on the embarrassed turtle that he was thirsty and needed to get up again. He sighed and walked over to the counter to poor himself some tea, keeping his back to his younger brother. He acknowledged the kettle had been boiled recently, also accepting he was probably in for a long and difficult conversation. Donatello cleared his throat, preparing himself in addressing his unpredictable brother.

"Leo, umm. I'm sorry I…disturbed you earlier."

"Donnie, I'm the one that should be sorry. I admit I've not been…myself lately."

"It's understandable. What do you remember?"

"I remember being in the dojo." He shut his eyes in anguish from the memories that followed the dojo; the severe pain and discomfort he felt; waking up and feeling like he was trapped in an alien body with a new limb, unable to move. He remembered hearing a dispute between his brothers and not having the power nor the will to stop them. He failed them.

"I don't remember much else to be honest, other than waking up on your floor and wondering where everyone was."

"Right." Donatello sat there twiddling his outer fingers whilst holding his hot beverage. Leonardo screwed up his face, not being able to stand the tension any longer and faced his brother.

"Donnie, is there something you want to talk to me about?" Arms out in exasperation.

"Well, there are a lot of things I probably should talk to you about."

"What about what happened between you and Raph? Where is Raph anyway?"

"You were awake?! Why didn't you say anything? You could've talked some sense in to Raph before he went storming off back to TCRI with Mikey!"

"Wait, they went back there?"

 _Oops!_ Thought Donatello. Before he started this discussion he advised himself not to address their brothers' new mission just yet. The eldest had enough to contend with. Leonardo quickly popped his brew back on the counter and suddenly leapt out of the room. Donatello sprinted in pursuit.

"Leo, wait. You can't just go out there. You need to recover."

"I've been out of the game long enough. I need to find them and bring them back here."

"Leo! Raph and Mikey can take care of themselves. If you're that worried, call them, but right now you need to sit down with me in the lab. I didn't get the chance to check you over before you went for a wander round the lair." Leo stared longingly at the exit.

"Come on." Donatello pulled his brother by the arm lightly in the opposite direction. It took some coaxing, but eventually they both made it.

...

Leonardo looked round the room of chaos; utensils and pieces of paper were spread across the floor; one of the cupboard doors was dented from Donatello's impact earlier, although Leo didn't remember being the cause of this.

"Was all this from your fight with Raph?"

"Umm...most of it, yes." Silence.

"You and I also had a slight…altercation."

Leonardo was concerned when he noticed the spots of blood on the floor.

"Whose is that?" Donatello wasn't sure what Leo was referring to, as he was taking his blood pressure, but quickly figured it out.

"Yours. It wasn't from an injury, just a wound opening up from the area where your tail has grown from."

"Okay." Donatello knew Leonardo was rapidly plunging in to thoughts of self-doubt and self-punishment. He knew he was blaming himself for all that has happened.

"Okay? Leo, why are you punishing yourself? This isn't your fault."

"Donnie, did I hurt you?"

"No! No, you didn't hurt me. Just…scared me a little, that's all."

"What happened?"

"You woke up and appeared to be panicking, so I tried to calm you down and tried talking to you, but you just glared at me. It was like something had taken over you." Leonardo felt even guiltier. He almost caused his brother harm. He honestly felt more like himself at this moment, but what could stop him from displaying aggression towards his brothers again?

"Blood pressure is normal, temperature is fine. Just a blood culture please." Leonardo reluctantly stretched out his right arm and made a fist as the scientist strapped a band round it.

"Leo, can I ask you…?"

"No…" Leo had a feeling he was going to be asked something deeply personal.

"What happened just now?"

"Donnie, I don't want to talk about it. Like I said, I've not been myself lately." Donatello knew to give it time as the eldest was not one for opening up easily. Whilst drawing the blood the leader surprisingly spoke.

"I don't know what came over me. The warmth was so…overwhelming. As soon as I started washing myself down, I experienced strange…sensations in certain areas. Ones that were new but not unpleasant. I couldn't help it." If Leo could sink any lower…He wanted to melt in to the floor and set in concrete, never to rise again.

"If it's any consolation, it's most likely another side effect to the contents of the syringe you were injected with. I analysed the sample while you were unconscious and the computer identified genes from a species of lizard. They are generally cold blooded, so your internal bodyworks probably went haywire when you were immersed in such a warm temperature. It looks like your body has a lot to adjust to."

"Hmm. What about our altercation?"

"You didn't attack me, and to be honest, I'm not sure. Mutagen is complicated enough! You don't need to imagine how complicated the combination of mixed DNA strands and already mutated genes can be." Donatello popped the needle on the side, pressed a piece of cotton wool on the blood drawn site and folded Leo's arm back so his palm was touching his shoulder.

"All done! Your bloods looked fine earlier, but I want to double check everything is in all in order. Okay?"

Leonardo held his flexed arm and sighed – the forlorn look was back. Donatello placed an arm round his downhearted brother and squeezed.

"Don't worry, Leo. We'll figure this out." Leo knelt his head against his brother's shoulder and smiled. He closed his eyes and, for the first time in the past few days, felt at home.


	15. Chapter 16

As Raphael and Michaelangelo headed back to the lair, they were alerted by a sounding alarm from one of Donatello's scanners, indicating Kirby was nearby.

"Well that was fast." Exclaimed Raphael.

"Well, where is he?" Michaelangelo rapidly looked at the sky and rotated 360 degrees, half expecting Kirby to be flying above them.

"According to this, he's by the Channel 6 building where me and Leo placed one of the beacons."

"Dude, I swear that building is cursed."

"C'mon." Raphael signalled for Mikey to follow him. "Donnie would never forgive us if we ignored it."

"Should we at least call the guys? Or April?"

"There's no time, Mikey! We have to get there now!" Raphael raced towards the prominent building which was only a few blocks away from their current position. Michaelangelo sprinted in pursuit with ease.

Once on an adjacent building, both turtles fired their grappling hooks which brought them to the rooftop. After scanning the area, both visually and with Donatello's tracker, there was no sign of Mr O'Neil.

"He must be here somewhere. Donnie's gizmo wouldn't have gone off otherwise."

"Unless…" Raphael's heart rose as the fear and realisation hit him.

"It is the one's called the turtles."

"Kraang were successful in modifying signals of the scanners belonging to the turtles."

"Whoa, that lizard dude was right, Raph."

"Kraang must capture them."

"You're not taking us anywhere!" Raphael quickly charged at the group of armed Kraang droids before they could defend themselves from his vicious attack. Michaelangelo had already flanked them with his new found speed, whipped his kusarigama chain round 3 droids at the back of the group and pulled them off the building.

"Let's make this quick!" Raphael retorted as he plunged his two sais into a droid that was invading his personal space. The sound of shearing metal tore through the air as the red banded turtle continued his onslaught. He suddenly froze in motion when a familiar looking dart landed on the ground in front of him. Looking in the opposite direction he witnessed two droids prepping their guns with more darts.

"Not this again." Mikey was already on the case and clashed the two offending droid heads together. Two alien Kraang quickly scurried across the rooftop, escaping from their robotic bodies which were now crumpled on the floor.

"C'mon, we should hurry back and tell Donnie."

"Already on it." Shouted Michaelangelo who was already dialling a number on his T-phone. He listened to his phone intently as the call continued to remain unanswered. Eventually Donatello's chirpy voicemail emerged.

"Dude, Donnie's not picking up."

"Maybe he's still with Leo. We need to get back to the lair and tell him his scanners have been compromised" ordered Raphael.

...

Numerous objects had been carefully laid out across the dojo floor which Leonardo endeavoured to avoid tripping over. He had deliberately placed stacks of books, old crockery and some of Mikey's spare water balloons in close proximity to each other as a training exercise. The aim was to avoid touching any of the objects whilst running through a number of simple katas – simple being the operative word with a tail to contend with. The idea emerged as he was beginning to get fed up of knocking small items with his extra limb such as the TV remote and accidentally scraping the doorframes as he moved from room to room. After finishing his second granola bar of the day and pondering the setup of the dojo, he started his warm-up routine of katas.

A few minutes in, the blue banded turtle felt confident in his movement and quickened the pace. He felt relieved to be in control once again as his katana blades gracefully cut through the air. As he closed his eyes, taking a deep breath in and slowly exhaling, he heard one of the crockery pieces shatter behind him. His eyes flicked open and looked to see if his peripheral vision could establish what he had knocked over and where.

 _Oops! Maybe I shouldn't have used Sensei's old tea set…_

As Leonardo turned to inspect the damage, his tail unintentionally whipped round and knocked one of the carefully stacked pile of books over. He watched in horror as they toppled over on to the floor.

 _Sigh…_ Leonardo's shoulders slumped as he pointed his katana blades towards the ground in disappointment.

"This is ridiculous." Leonardo muttered to himself, but then realised in shock of what he had just said, wanting to retract his statement immediately.

 _No, I won't give up! This is going to take time, practice and patience._

As he closed his eyes once again to concentrate and refocus, an annoying ringing noise was emanating from outside the dojo.

"Donnie, are you going to get that? Donnie?" The eldest found it odd that his brother did not respond, especially when the latter had been watching over him like a hawk the past few hours.

 _Maybe he's deep in his work, or maybe he's actually getting some sleep. Hopefully the latter, but I'd better check up on him._

Leonardo reluctantly sheathed his katanas and rolled his eyes as he knocked over another stack of books. As he made his way to Don's laboratory, a feeling of dread crept over him. The lair was eerily quiet, and something didn't seem right.

"Donnie?" He quickly raced over to the lab and stood in fear as he witnessed his purple banded brother lying unconscious on the floor. Donatello's bow staff lay loosely in his hand.

"Donnie!" The leader sprinted over to his brother's lifeless form and knelt close to the engineer's plastron. His breathing was shallow and his pulse was racing. Leonardo scanned his brother and confirmed there were no visible injuries he could see initially. As he tried to turn the unconscious terrapin on to his side, his scaly hand quickly retracted from Donatello's skin which was cold and clammy. Was Donatello in shock? It frightened him that his brother was not responding despite calling to him a number of times and trying to shake him awake. A second wave of dread suddenly hit Leonardo.

 _Oh shell, did I do this? What have I done…_


	16. Chapter 17

Donatello wearily pried his eyes open, feeling the cold hard floor against his left side. He found it difficult to focus on the soft voice of his older brother calling to him as his brain was foggy and confused.

"L-Leo? Is that you?"

"Hey Donnie, I'm here. Are you okay?"

"Wh…where are we?" Donatello gradually rose from the floor, propping himself up on his elbows and then his hands until he was sat in an upright position. He instinctively looked round for some pain killers for his throbbing head.

"We're in your lab, Donnie. I found you unconscious on the floor. If I'm being honest, you don't look so good. Can you remember what happened?" Leonardo simultaneously hoped and dreaded that his brother would recall what happened. He feared Donatello would have a concussion otherwise, and whether Leo himself had caused it.

"I remember trying out a new formula for Mikey's puritis. I got up for some printed results…" Donatello gazed distantly across the room and pointed to the printer to help him retrace his steps.

"And that's it. That's all I remember…" Leonardo couldn't shrug off his concern.

"Donnie, are you sure you're alright?" Donatello refused to give an honest answer.

"You've been working yourself too hard, working to the point of exhaustion. This needs to stop." Leonardo advised - to which Donatello retaliated.

"Then what would you have me do, Leo?! Let you and Mikey live with unstable and unpredictable mutations for the rest of your lives that could kill you? There IS no one else. I HAVE to fix this!" Leonardo suddenly went quiet as the realisation suddenly hit him.

"What do you mean it could kill us?"

"Your mutation is still progressing, and Mikey's too. Genetic reprogramming - something is bound to go wrong along the chain." Doubts began to cloud Leonardo's focused train of thought which he tried to push back.

"You don't know that."

"No, I don't, and it scares me." Donatello brought his knees up to his chest and rested his arms and head against them as he tried to muffle his sobbing.

Leonardo immediately scooted over to confide in him and wrapped a scaly arm round his distraught brother.

"Donnie, this isn't your fault. It was in your best intention to go and rescue Kirby - for April. We've been through worse before, right? Alien invasions. Shredder. My cooking."

Donatello gave a quick smile. As Leonardo looked round the room, he noticed how many packets of Tylenol extra strength and aspirin had been thrown in the recycling bin.

"Donnie?"

"Hmm?"

"How many pain killers have you had lately?"

"A few."

"Define a few?"

"No more than two every four hours, as prescribed."

"Of each? Do you think these have something to do with you passing out?"

"If I don't take them I can't concentrate. If I can't concentrate I can't focus on finding any answers. I can't do anything." Donatello placed his head in between his elbows as he rose his arms over his head in an attempt to hide his shame.

"Are these for your headaches?"

"Yeah. They've been really bad lately. I know what migraines are and this isn't one of them."

"When did they start?"

"Shortly after we got back from the Kraang lab."

"Aaaaand you didn't think to mention this sooner?"

"Well, a lot has been going on, okay?

"No Donnie, it's not. Come on. Results take time, so they can wait while you rest." Leonardo shoved an arm under Donatello's right arm and hauled him to standing position.

"Now, you're going to go get some sleep, and no fretting. REM sleep and dreams are good for ideas."

"Who made you the expert?"

"I'm not. I was just hoping you'd be too tired to argue back. I'll keep an eye out for Raph and Mikey."

Leo was right, Donatello was too tired to argue.

* * *

As Raphael was about to call his two brothers back at the lair, he suddenly received an incoming call.

"April?" Raphael had to press himself right against the speaker in order to hear her whispered voice.

"Raph! Thank goodness. Listen, I'm down by the abandoned bridge rail terminal, and I think I'm being followed."

"April, what are you doing down there?"

"I think the Kraang are up to something. They keep patrolling this area and…"

"April, Kraang have scout parties everywhere. What makes you think they're up to something in that area?"

"I found something, and I think you should take a look. Are you at the lair?" The red banded turtle looked round to survey where he was.

"No, luckily Mikey and I are only a few blocks away. Donnie and Leo are back at the lair. They aren't gonna like this."

"That'sgreattalklaterIgottagobye." Raphael looked at the dropped call message in disgust. He just about made out what she said in her haste to finish the call. He knew his smartass brother was not going to like this for many reasons, mainly because April was getting in to mischief once again.

"Alright, new plan. We're gonna head down ta that creepy rail junction that's been abandoned for months."

"Was that April? Is April ok?" Michaelangelo came closer in concern.

"Not sure. We should go check it out. Sounds like she may need our help. Drop Donnie a message for me will ya?"

It was difficult for the two turtles to see the desolate underground when there was no electricity to power the lights. The terminal had been abandoned for some time, apart from the odd group of gangsters looking to do business or other criminal activities. On a normal night out on patrol, Raphael wouldn't have minded being in this environment, but he knew this was a different kind of mission, and really he and Michaelangelo shouldn't be here. He could just about see and avoid the supporting steel structures as his eyes adjusted to the dark. He also spotted a side door which didn't look as dusty as the rest of the place.

"Mikey, over here." Whilst gesturing to his younger brother, he turned the handle and pushed.

"Maybe you need to pull instead of push." Despite Michaelangelo's fair comment, Raphael proceeded to break the door down by kicking near the weakened hinges. The youngest flinched as the door fell forward, hitting the floor with a loud bang that echoed and bounced off the steel structures. Both turtles prepared themselves for a not so surprise attack – one which ironically never came. After a couple of minutes of apprehension, they started walking down a dimly lit set of descending stairs. The further they travelled the warmer they felt.

"What do you think is down there?" Michaelangelo gestured the bottom of the stairs which they were rapidly approaching.

"There's only one way to find out. C'mon."

"Dude, this is almost as creepy as that movie we saw when the welcome party went in to the basement of the crashed alien space ship."

As they reached the bottom, they came across a cavern with small lights the colour of freshly expelled lava. Raphael felt it was warm enough to be volcano. There were five rocky coves, each with a pool of the same orange coated substance spread around the area; each one encapsulating a number of small dark pods. In the centre of the cavern was a hexagonal armoured black device with six pillars. Although it was fairly wide, it was only as high as Raphael's waist line. The red banded turtle knelt down and studied its aesthetics whilst his younger brother let curiosity get the better of him.

"Whoa dude. I think these are eggs." Raphael quickly darted round and rushed over to Michaelangelo.

"They're not mutant wasp eggs are they?" Neither wanted to be reminded of the time three of them were brainwashed in to looking after a mutated wasp's egg and potentially being eaten.

"Nah bro, these are a different colour." Michaelangelo pressed himself against one of the pods.

"And they are a lot less noisy. What should we do?"

"I wanna know what this thing is." Raphael backtracked to the glowing device in the middle of the room a few meters away.

"Whatever it is, it can't be good."

"Maybe it's to keep the eggs warm."

"Well in that case we should find a way to turn it off."

"Whoa, Raph. Hold up. What're you doing? We don't know what these things are." Michaelangelo struggled to hush his exclamation.

"They're obviously Kraang experiments, c'mon. Whatever they're cooking up in here, we need to destroy them."

"Well, even if you do destroy them, what about the thing that laid them? It could just lay more - like that same alien movie we watched. The freaky alien mother came back and killed the scout party. Only one dude survived."

"We'll deal with that later if it comes to it. Now help me figure this thing out. If only Donnie were here."

"If he got my message, hopefully any minute now."

"What?! I didn't say tell him where we were."

"I didn't. I just said April's in trouble, gonna investigate."

"What?! That's worse shellferbrains."

"You said text him!"

"Urgh, forget it. See if you can ring him."

After staring at the phone's screen and creasing his brow for a short while, the youngest leapt around the cavern reaching up towards the ceiling with his T-phone in hand. Raphael was rather unnerved when he witnessed his brother sticking himself to the ceiling (upside-down).

"What're you doing?"

"Dude, there's no signal down here. It's ringing out but not getting through."

"Maybe there's an off button or some…" Raphael never managed to finish his sentence as he was interrupted by a soft whirring noise. As he tentatively hovered over the armour plated device, he noticed a circular dome hidden in the centre beginning to grow in brightness. The whirring quickly increased in volume in correlation to the dome's light intensifying inside.

"Mikey MOVE!"

Both turtles dashed for what limited cover was in the vicinity as a high pitched whine and a wave of brightly coloured energy erupted from the device. A beam that shot vertically upwards to the ceiling, extraordinarily close to where Michaelangelo had been reaching for a signal. Then an orange wave rippled outwards throughout the cavern. The ceiling above Raphael began to crumble as small rough fragments broke off and fell to the ground. Fear shot Raphael down as he realised the cavern was literally caving in on itself, and he could no longer see his brother amidst the chaos. His heart took an extra leap in response to the cracking noise above him as the ceiling cascaded down on him.

"Ah shell…"


End file.
